Preheat your oven to 300°F (150°C).

In a large mixing bowl, combine the Rice Chex, Wheat Chex, pretzel sticks, pecans, and dried cranberries.

Melt the butter in a small saucepan and add brown sugar, pumpkin puree, pumpkin pie spice, and vanilla. Stir until smooth.

Pour the pumpkin spice mixture over the Chex mixture and stir gently to coat.

Spread the mixture evenly on a lined baking sheet.

Bake for 45 minutes, stirring every 15 minutes.

Allow to cool completely on the baking sheet.

Transfer to an airtight container for storage.